AWS Certified Solutions Architect – Associate (SAA-C03)Design Cost-Optimized ArchitecturesHard
A large enterprise is migrating its legacy on-premises applications to AWS. Some of these applications require dedicated physical servers for licensing compliance and regulatory reasons. The enterprise wants to minimize operational costs while meeting these requirements. Which EC2 purchasing option should they use?
- AOn-Demand Instances on a Dedicated Host
- BSavings Plans for Compute on a Dedicated Instance
- CReserved Instances on a Dedicated Host
- DSpot Instances on a Dedicated Host
Show answer & explanationAnswer & explanation
Correct answer: C. Reserved Instances on a Dedicated Host
Reserved Instances on a Dedicated Host combine the cost savings of Reserved Instances with the physical isolation and licensing benefits of Dedicated Hosts. This is the most cost-effective solution for long-term, predictable workloads that require dedicated physical servers.
Why the other options are wrong
- A. On-Demand Instances on a Dedicated Host would provide the dedicated physical server but would be significantly more expensive than using Reserved Instances for a long-term workload.
- B. Savings Plans apply to EC2 instance usage across different types, but for Dedicated Hosts, the most direct and significant cost reduction for predictable usage comes from Reserved Instances associated with the host itself, not just the compute running on it. Savings Plans can apply to the instances *on* the host, but the host itself is best optimized with RIs.
- D. Spot Instances are not available on Dedicated Hosts because Dedicated Hosts require a specific physical server allocation, which is contrary to the interruptible nature of Spot Instances.
Reserved Instances on Dedicated Hosts
Reserved Instances can be purchased for Dedicated Hosts, providing significant cost savings for long-term, predictable usage of dedicated physical servers.
- Combines benefits of Dedicated Hosts (physical isolation) with RI cost savings.
- Ideal for licensing requirements that mandate dedicated hardware.
- Requires a 1-year or 3-year commitment.
- Offers substantial discounts compared to On-Demand Dedicated Hosts.
Memory trick: Reserved for Dedication, Reduces the Bill's Temptation.